Performance Engine Building - Off-The-Shelf Steam

Easy 414hp Gain With a Little Boost!

Let’s not kid ourselves; the fine art of cylinder head porting, along with trick engine-building techniques, can go a long way with closed-course competition applications. However, for the average do-it-yourselfer who wants big numbers, whether it’s on the dyno or at the track, we can take solace knowing that today’s manufacturers are producing components that will transform any weekend engine builder into a local hero. That’s right; we’re talking about a level of performance that was until recently reserved for those with deep pockets.

The recipe is simple: Start with a solid foundation, be it a mild or big cubic-inch stroker assembly and then add the induction of your choice. Given the caliber of cylinder heads and power adders available, it’s only a matter of deciding how far you want to go. In our case, we wanted to put together a blow-through supercharger combination that was mild enough for cruise nights yet powerful enough to throw down numbers on any given test and tune session.

This month’s featured combination is the first of a two-part series showing just how radical you can get. For the first rendition, we started with a standard 9.8-inch deck Dart Big M block; Dart built a limited supply of complete short-blocks as a test program and we were fortunate enough to get our hands on one. Don’t fret, even though this came to us complete, the internals are widely available from most speed shops. Inside, the rotating assembly consists of a forged Eagle Specialties 4.00-inch crankshaft, and forged Engine Pro 6.385-inch rods with Keith Black flat-top pistons.

Working our way up, we wanted a set of heavy breathers that would support upper-level horsepower while being able to evacuate the spent gases in a hurry. Our cylinder heads of choice were the Brodix BB-3 Xtras with its line of HV 2000 intake manifold. For the power adder, we went with Vortech’s Ysi supercharger and relied on our trusty Holley 750hp carburetor that’s been modified by The Carb Shop. At the center of our creation, we have a custom-grind COMP bumpstick, including a complete COMP valvetrain. With everything in check, our 454ci produced 2.1 hp/ci, translating into 965 hp and 877 lb-ft! It’s impressive to say the least, so follow along and see what it takes to replicate the combination for yourself.

The Carb Shop

To say we’ve been fortunate to work with The Carb Shop out of Ontario, California, would be a complete understatement. For the past several years, they’ve been an integral part of our blow-through supercharger coverage and, for a lack of better words, they’re the real heroes behind our successful dyno and track sessions.

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And if you didn’t already know, they’re gearheads well versed in building everything from performance carburetors to engines, even fielding their own cars down the dragstrip. It’s this type of R&D that has put them on the leading edge of blow-through technology. More importantly for your wallet, their custom-order blow-through carbs are very affordable and can be had for $840 complete or $450 by sending in your own to get modified. For more information, head over to www.customcarbs.com.

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Performance Engine Building - Off-The-Shelf Steam

As mentioned earlier, our 9.800-inch-deck Dart Sportsman Big M block came fully assembled. In the 454 configuration, our block came with a 4.250-inch bore and a 4-inch stroke crankshaft. Should you want to go bigger, this block can safely handle up to a 4.625x4.750-inch bore and stroke; anything larger than that and you’ll want to step up to the 10.200-inch tall-deck block. The all-forged rotating assembly consists of an Eagle Specialties crankshaft, Engine Pro H-beam rods, and Keith Black pistons.

The flat-top KB pistons featured deep valve reliefs, combined with the Brodix BB-3 Xtra Oval 332 cylinder heads and its 119cc chambers; our blower-friendly combination came in at 8:1 compression.

For oiling, we opted for a Moroso billet aluminum spur gear oil pump. This unit has special anticavitation slots, feeder grooves, and an enlarged bypass area that bleeds oil back to the inlet side of the pump. All this ensures a smooth, reliable operation, especially critical in a blown application.

To actuate the valves, a custom-grind COMP Cams solid roller was spec’d out for us by The Carb Shop. Built on a 112 LSA, it featured a split-duration of 245/250 degrees at 0.050 with a single-pattern 0.650-inch lift on the intake and exhaust.

For lifters, we ordered a set of COMP Cams’ latest Endure-X pieces. These stout units come with a removable link bar, designed to receive a constant flow of pressurized oil to its needle bearing assembly, has precision-sorted bearings to help distribute the load evenly, and a Tool Steel axle for longevity. Best of all, they’re completely rebuildable.

Traditional timing chains work well, but when it comes to high-performance combos, it’s hard to beat the benefits of a beltdrive system; cam adjustments can be handled quickly, cam swaps become a breeze, and the belt acts as a secondary damper, helping to reduce crankshaft harmonics. To keep ours in check, we went with a COMP Cams Hi-Tech beltdrive system (PN 6200).

Keeping the oil in place is a six-quart Moroso oil pan. Inside are several notable features, including the kicked-out sump and crank scraper, the unidirectional windage screen, and a trapdoor baffling for better oil control. We also ordered the matching dipstick and oil stud kit.

To seal the heads into place, we used a fresh set of 0.053-inch-thick Fel-Pro multilayer steel gaskets.

Conventional 24-degree cylinder heads have come a long way and Brodix’s CNC BB-3 Xtra oval-port 332s can flow a copious amount of air. At 0.700-inch lift, these jewels already flow 416 cfm on the intake and 290 cfm on the exhaust side, making it ideal for big-inch and power adder combinations. For springs, ours were outfitted with 1.625-inch roller springs with pressures at 260 pounds closed and 790 pounds open. Brodix also offers optional 1.645-inch roller springs with increased pressures at 315 pounds closed and 915 pounds open.

Getting the mixture into the cylinders is a 2.300-inch intake valve while the 1.880-inch exhaust valve gets it out.

It isn’t uncommon to have big boosted applications push the cylinder heads off the block. To counter this, we secured the heads in place with a set of ARP head studs over their head bolt counterpart and torqued them to 70 ft-lb with moly-lube.

Up top we used a set of COMP 7/16-diameter 1.7:1 ratio Ultra Pro Magnum roller rockers. We’ve used these on many builds with great success and like the unique web-style design, which helps to increase strength and rigidity. We also installed COMP Cams’ Dual Taper 3/8- to 7/16-inch pushrods with 0.125 wall, measuring in at 9.400 and 8.650 inches.

We’ve been looking for a reason to get our hands on COMP’s latest DuPont Black-Wrinkle powdercoat-finished valve covers. For a pair of Benjamins, these beauties come complete with two chrome breathers and welded baffles, and are tall enough to house aftermarket valvetrains.

To seal the lifter valley, we installed a Brodix HV 2000 manifold. We originally selected the BM 2017-O version that requires a 4500-series carburetor; however, we decided to stick with a 4150-series to show that a properly built 750-cfm carburetor could easily support upper horsepower levels. The Moroso spacer shown here is a modified unit that allowed us to monitor fuel temperature readings. The black hose exiting the manifold ties into the bypass valve, which releases the high volume of air when you let go of the loud pedal.

Blow-through carbureted superchargers are more popular than ever and this is what you need to get the job done right the first time. Thanks to The Carb Shop, we’ve used this particular carburetor on everything from mild 500 hp to well over 1,100hp combinations. We’ve shown complete builds in the past, and you can access that story for full details on our site at chevyhiperformance.com.

Vortech Engineering’s Ysi supercharger can pack a punch and has powered a number of class cars well into 8-second quarter-mile times. Max impeller speed is rated at 65,000 rpm with a max flow rating of 1,600 cfm. For our cog pulley combination, we used an 80-tooth lower with a 29-tooth upper, which produced 16.7 psi of boost. CHP

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